<template>
  <div class='xtx-carousel' @mouseenter="stop()" @mouseleave="start()">
    <!-- 轮播图展示区 -->
    <ul class="carousel-body">
      <li class="carousel-item " v-for="(item, i) in sliders" :key="item.id" :class="{ fade: index === i }">
        <!-- 图片 -->
        <RouterLink v-if="item.hrefUrl" :to="item.hrefUrl">
          <img v-lazy="item.imgUrl" alt="">
        </RouterLink>
        <!-- 商品列表 -->
        <div v-else class="slider">
          <RouterLink v-for="goods in item" :key="goods.id" :to="`/product/${goods.id}`">
            <img v-lazy="goods.picture" alt="">
            <p class="name ellipsis">{{ goods.name }}</p>
            <p class="price">&yen;{{ goods.price }}</p>
          </RouterLink>
        </div>
      </li>
    </ul>
    <!-- 切换图片的按钮 -->
    <a href="javascript:;" class="carousel-btn prev"><i class="iconfont icon-angle-left" @click="prevImg(-1)"></i></a>
    <a href="javascript:;" class="carousel-btn next"><i class="iconfont icon-angle-right" @click="prevImg(1)"></i></a>
    <!-- 白点区 -->
    <div class="carousel-indicator">
      <span v-for="(item, i)  in sliders" :key="item.id" :class="{ active: index === i }" @mouseover="index = i"></span>
    </div>
  </div>
</template>

<script lang="ts">
import { ref, watch, onUnmounted } from 'vue'
export default {
  name: 'XtxCarousel',
  props: {
    // 拿到数据
    sliders: {
      type: [Array, Object],
      default: () => []
    },
    // 自动播间隔时间初始值为3s,也可以由使用者决定
    duration: {
      type: Number,
      default: 3000
    },
    //有使用者决定是否开启自动播放功能
    autoPlay: {
      type: Boolean,
      default: false
    },

  },
  setup(props) {
    // 默认显示的图片的索引
    const index: any = ref(0)
    // 1.图片切换逻辑
    const prevImg = (num) => {
      const newIndex = index.value + num
      // 图片的索引大于等于数组的长度时
      if (newIndex >= props.sliders.length) {
        index.value = 0
        return
        // 图片的索引小于0时
      } else if (newIndex < 0) {
        index.value = props.sliders.length - 1
        return
      } else {
        index.value = newIndex
      }
    }
    // 2.自动播放，暴露自动轮播属性，设置了就自动轮播
    let timer = null
    const autoPlayFn = () => {
      clearInterval(timer)
      timer = setInterval(() => {
        index.value++
        if (index.value >= props.sliders.length) {
          index.value = 0
        }
      }, props.duration)
    }
    // 监听数据的变化从而开启自动播放
    watch(() => props.sliders, (newVal) => {
      // 有数据&开启自动播放，才调用自动播放函数
      if (newVal.length && props.autoPlay) {
        index.value = 0
        autoPlayFn()
      }
    }, { immediate: true })
    // 3.如果有自动播放，鼠标进入离开，暂停，开启
    const stop = () => {
      if (timer) clearInterval(timer)
    }
    const start = () => {
      if (props.sliders.length && props.autoPlay) {
        autoPlayFn()
      }
    }
    // 4.组件销毁时清除定时器
    onUnmounted(() => {
      clearInterval(timer)
    })
    return {
      index,
      prevImg,
      autoPlayFn,
      stop,
      start
    }
  }
}

</script>
<style lang="less">
@import '../../assets/styles/common.less';
@import '../../assets/styles/variables.less';

.xtx-carousel {
  position: relative;
  width: 100%;
  height: 100%;
  min-width: 300px;
  min-height: 150px;


  .carousel {
    &-body {
      width: 100%;
      height: 100%;
    }

    &-item {
      width: 100%;
      height: 100%;
      position: absolute;
      left: 0;
      top: 0;
      opacity: 0;
      transition: opacity 0.5s linear;

      // 轮播商品
      .slider {
        display: flex;
        justify-content: space-around;
        padding: 0 40px;

        >a {
          width: 240px;
          text-align: center;

          img {
            padding: 20px;
            width: 230px !important;
            height: 230px !important;
          }

          .name {
            font-size: 16px;
            color: #666;
            padding: 0 40px;
          }

          .price {
            font-size: 16px;
            color: @priceColor;
            margin-top: 15px;
          }
        }
      }

      &.fade {
        opacity: 1;
        z-index: 1;
      }

      img {
        width: 100%;
        height: 100%;
      }
    }

    &-indicator {
      position: absolute;
      left: 0;
      bottom: 20px;
      z-index: 2;
      width: 100%;
      text-align: center;

      span {
        display: inline-block;
        width: 12px;
        height: 12px;
        background: rgba(0, 0, 0, 0.2);
        border-radius: 50%;
        cursor: pointer;

        ~span {
          margin-left: 12px;
        }

        &.active {
          background: #fff;
        }
      }

    }

    &-btn {
      width: 44px;
      height: 44px;
      background: rgba(0, 0, 0, .2);
      color: #fff;
      border-radius: 50%;
      position: absolute;
      top: 228px;
      z-index: 2;
      text-align: center;
      line-height: 44px;
      opacity: 0;
      transition: all 0.5s;

      &.prev {
        left: 20px;
      }

      &.next {
        right: 20px;
      }
    }
  }

  &:hover {
    .carousel-btn {
      opacity: 1;
    }
  }
}
</style>